New restrictions for travelers from people from six mainly Muslim countries and all refugees have taken effect in the United States.

Under the temporary rules, which took effect at 8 p.m. Washington time on June 29 (2 a.m. on June 30 Prague time), citizens of Syria, Sudan, Somalia, Libya, Iran, and Yemen without “close” family relationship or “formal” tries to a U.S. organization could be denied visas and barred entry.

With all valid visa holders still being able to travel, there was no sign of the chaos that affected airports in January when the original ban was released.

But the travel ban faced a new court challenge, with the state of Hawaii requesting that a federal judge clarify whether the government violated instructions from the Supreme Court.

The Supreme Court on June 26 lifted lower court decisions blocking President Donald Trump's executive order banning visitors from the six countries and suspending the U.S. refugee program.

But the court said the 90-day travel ban would not apply to visitors who have a "credible claim of a bona fide relationship with a person or entity in the United States." The 120-day ban on refugees is also being allowed to take effect on a similar, limited basis.

According to the new guidelines set by the Trump administration earlier this week, people with a parent, spouse, child, son- or daughter-in-law, or sibling in the United States will be able to enter the country.

In a last minute change, the definition of "close" relationship was extended to also include fiances.

However, the definition excludes grandparents, grandchildren, aunts, uncles, nieces, nephews, cousins, as well as brothers- and sisters-in-law.

Also exempt from the ban are those with ties to U.S. organizations, but such relationships must be “formal, documented, and formed in the ordinary course, rather than for the purpose of evading" the executive order.

Those who already hold valid visas and dual citizens who travel on a passport from an unaffected country will be allowed entry.

As travel officials across the United States made final preparations for implementing the ban, opponents were preparing new legal challenges.

Moments before the revised travel ban took effect, Hawaii asked a federal judge to determine whether the government interpreted the Supreme Court's instructions too narrowly in defining who is concerned by the ban and who’s excluded.

Hawaii called the refusal to recognize grandparents and other relatives as an acceptable family relationship "a plain violation of the Supreme Court's command."

Hawaii Attorney General Doug Chin asked District Judge Derrick Watson in Honolulu to issue an order "as soon as possible" clarifying how the court's ruling should be interpreted.

The original travel ban, released in January, was blocked by court. A revised ban was halted by Watson before it was supposed to go into force in March.

Trump says his executive order is needed to stop terrorists entering the United States, but some critics consider the travel ban as a ban on Muslims.

The Supreme Court is expected to make a final decision on the ban when it begins its next session in October.